Polishing brush

ABSTRACT

A polishing brush ( 1 ) includes grinding element bundles ( 22 ) each including wire-shaped grinding elements ( 21 ) formed of an assembly of inorganic filaments impregnated and solidified with resin, and a grinding element holder ( 23 ) that holds the grinding element bundles ( 22 ). The grinding element holder ( 23 ) has an annular grinding element holding groove ( 28 ), and an adhesive ( 29 ) is filled in the grinding element holding groove ( 28 ). Respective base end portions ( 22   a ) of the grinding element bundles ( 22 ) are inserted in the grinding element holding groove ( 28 ) in such a state as to be kept apart from each other and are fixed to the grinding element holder ( 23 ) with the adhesive ( 29 ). Even when the diameter size or the like of each grinding element bundle ( 22 ) is larger than the width of the groove, the grinding element bundles ( 22 ) are deformed to conform to the groove, thereby being inserted into the groove.

FIELD

The present invention relates to a polishing brush having a grinding element holder holding a plurality of wire-shaped grinding elements.

BACKGROUND

Such a polishing brush is described in Patent Literature 1. In this literature, a plurality of wire-shaped grinding elements are subdivided to form a plurality of grinding element bundles, and the grinding element bundles are held apart from each other in a grinding element holder. Each grinding element bundle has a circular shape in cross section, and the grinding element holder has a plurality of holding holes for holding the grinding element bundles. The holding holes are circular and disposed apart from each other. The grinding element bundles have respective base end portions inserted in the holding holes and fixed to the grinding element holder with an adhesive filling the holding holes.

CITATION LIST Patent Literature

Patent Literature 1: WO2004/009239

SUMMARY Technical Problem

In a polishing brush having a grinding element bundle held in a holding hole with a shape adapted to the cross-sectional shape of the bundle, if the diameter size of the grinding element bundle is larger than the inner diameter size of the holding hole or the shape of the grinding element bundle differs from the shape of the holding hole at the time of manufacturing, the grinding element bundle fails to be inserted in the holding hole. Therefore, at the time of manufacturing of the polishing brush, it is necessary to strictly control the diameter dimension and shape of the grinding element bundle of wire-shaped grinding elements within a predetermined range corresponding to the inner diameter size and shape of the holding hole provided in the grinding element holder.

In this respect, an object of the present invention is to provide a polishing brush in which a plurality of wire-shaped grinding elements can be readily held in the grinding element holder.

Solution to Problem

In order to solve the problem above, the present invention provides a polishing brush including a plurality of wire-shaped grinding elements and a grinding element holder holding the wire-shaped grinding elements, characterized in that the grinding element holder has a groove, and that first end portions of the wire-shaped grinding elements are inserted in the groove and fixed to the grinding element holder with an adhesive filling the groove.

According to the present invention, since the wire-shaped grinding elements are inserted in the groove and fixed with an adhesive, it is possible to hold the wire-shaped grinding elements in the grinding element holder without strictly controlling the shape of the wire-shaped grinding elements.

In the present invention, the wire-shaped grinding elements may be subdivided to form a plurality of grinding element bundles, and the grinding element bundles may be fixed to the grinding element holder in such a state as to be kept apart from each other. With this configuration, even when the diameter size or shape of each grinding element bundle is larger than the width of the groove, the grinding element bundle is deformed to conform to the groove whereby the base end portion of the grinding element bundle can be inserted in the groove. Thus, even when each grinding element bundle has a different diameter size or shape, the grinding element bundles can be held in the grinding element holder. Furthermore, in this configuration, the grinding element bundles held in the grinding element holder are kept apart from each other to allow chips to be efficiently ejected during grinding work. In addition, since the grinding element bundles held in the grinding element holder are kept apart from each other, the heat dissipation effect is high. Moreover, when compared with a case in which the wire-shaped grinding elements are held without a gap, the polishing brush can be formed with a smaller amount of grinding elements.

In the present invention, the groove may be an annular groove formed around the axis of center of rotation, and the grinding element bundles may be inserted at regular intervals in the annular groove. With this configuration, a cup-shaped polishing brush or a wheel brush can be readily manufactured.

In the present invention, each of the grinding element bundles may have a circular shape in cross section in a direction orthogonal to a length direction of each of the wire-shaped grinding elements at an end portion of the grinding element bundle inserted in the groove. This configuration enables the grinding element bundle to be held in the grinding element holder without strictly controlling the diameter size of the grinding element bundle.

In the present invention, each of the wire-shaped grinding elements may be formed of an assembly of inorganic filaments impregnated and solidified with resin. Since the wire-shaped grinding element formed of inorganic filaments has high hardness, the grinding/polishing capability of the polishing brush is improved even with a small amount of grinding elements.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a polishing brush in a first embodiment.

FIG. 2 is an exploded perspective view of the polishing brush.

FIG. 3 is an illustration of the polishing brush and the polishing brush body.

FIG. 4 is an illustration of a polishing brush in a second embodiment.

DESCRIPTION OF EMBODIMENTS

A polishing brush to which the present invention is applied will be described below with reference to the drawings. In the following description, it is assumed that the direction of the axis of center of rotation of the polishing brush is the top-bottom direction of the polishing brush in accordance with to the top-bottom direction in FIG. 1, for the sake of convenience.

First Embodiment

FIG. 1 is an illustration of a polishing brush to which the present invention is applied. FIG. 2 is an exploded perspective view showing the polishing brush shown in FIG. 1 disassembled into a brush case and a polishing brush body. FIG. 3(a) is a cross-sectional view of the polishing brush cut through a portion fixed with screws, FIG. 3(b) is a bottom view of the polishing brush, and FIG. 3(c) is a longitudinal sectional view of the polishing brush body.

As shown in FIG. 1, the polishing brush 1 in this embodiment includes a cup-shaped brush case 6 having a shank 5 coupled to the head of a machine tool (grinder), a polishing brush body 7 having an upper side portion inserted in the brush case 6, and screws 8 and 9 for fixing the polishing brush body 7 to a predetermined position in the brush case 6.

The brush case 6 is made of metal and includes a cylinder-shaped peripheral wall 11 and a circular top plate 12 closing the upper end opening of the peripheral wall 11. The shank 5 extends upward from the central portion of the top plate 12. A rod-shaped support shaft 13 extends downward from the central portion of the lower surface of the top plate 12. The support shaft 13, the shank 5, and the peripheral wall 11 are coaxial. The peripheral wall 11 of the brush case 6 has guide holes 14 and 15 extending in the shape of a groove parallel to the axis of center of rotation L. The guide holes 14 and 15 are formed in point symmetry with the axis of center of rotation L interposed therebetween. In this embodiment, the peripheral wall 11 of the brush case 6 is made of aluminum, and the support shaft 13 is made of stainless steel.

As shown in FIG. 2, the polishing brush body 7 includes a plurality of grinding element bundles 22, each formed of a plurality of wire-shaped grinding elements 21, and an annular grinding element holder 23 holding the grinding element bundles 22. The grinding element holder 23 is made of metal. The grinding element holder 23 has a center hole 24, which is a shaft hole allowing the support shaft 13 to pass through. The grinding element holder 23 has a pair of screw holes 25 and 26 at point-symmetric positions with the axis of center of rotation L interposed therebetween. As shown in FIG. 3(a), the screw holes 25 and 26 pass through the grinding element holder 23 in the radius direction.

As shown in FIG. 3(b) and FIG. 3(c), the grinding element holder 23 has an annular grinding element holding groove (groove) 28 formed around the axis of center of rotation L on its lower end surface, namely, a grinding member holding surface 27. The grinding element bundles 22 have respective base end portions 22 a inserted in the grinding element holding groove 28 in such a state as to be kept apart from each other and are fixed to the grinding element holder 23 with an adhesive 29 filling the grinding element holding groove 28. The adhesive 29 is, for example, of a silicone resin type or an epoxy resin type. As shown in FIG. 3(b), in the first embodiment, each grinding element bundle 22 is a bundle shaped in a circle. More specifically, each grinding element bundle 22 has a circular shape in cross section in a direction orthogonal to the length direction of each wire-shaped grinding element 21 at an end portion of the grinding element bundle 22 inserted in the grinding element holding groove 28. The grinding element bundles 22 are inserted and fixed at regular intervals in the grinding element holding groove 28. In a state in which the grinding element bundles 22 are fixed to the grinding element holder 23, the grinding element bundles 22 extend downward from the grinding member holding surface 27 of the grinding element holder 23.

Each wire-shaped grinding element 21 is formed of an assembly of alumina filaments as inorganic filaments impregnated and hardened with a thermosetting binder resin such as silicone resin, phenol resin, epoxy resin, polyimide resin, polymaleimide resin, unsaturated polyester resin, and urethane resin. A thermoplastic resin such as nylon may be used as the binder resin. In the first embodiment, the filament assembly is a group of 250 to 3000 alumina filaments having a fiber diameter of 8 to 50 μm. The diameter of the filament assembly is 0.1 mm to 2 mm. The filament assembly may be twisted.

Here, when the base end portion 22 a of each grinding element bundle 22 is inserted into the grinding element holding groove 28, the subdivided wire-shaped grinding elements 21 are simply put together and bundled. The wire-shaped grinding elements 21 subdivided and bundled are tied together with the adhesive 29 in the form of the grinding element bundle 22 when being fixed to the grinding element holder 23 with the adhesive 29 in the grinding element holding groove 28.

To build the polishing brush 1 with the brush case 6 and the polishing brush body 7, first, the support shaft 13 is passed through the center hole 24 (shaft hole) of the grinding element holder 23, and the upper portion of the polishing brush body 7 (the side of the grinding element holder 23) is inserted in the inside of the brush case 6. Then, the screws 8 and 9 are put through the guide holes 14 and 15 from the outer peripheral side of the brush case 6, and the screws 8 and 9 are secured to the screw holes 25 and 26 of the grinding element holder 23. In doing so, the screws 8 and 9 are tightened until the tip ends of the shafts of the screws 8 and 9 abut on the outer peripheral surface of the support shaft 13. The grinding element holder 23 is thus fixed to the support shaft 13 of the brush case 6 through the screws 8 and 9. In the outer peripheral surface of the support shaft 13, the region and the vicinity thereof in abutment with the tip ends of the screws 8 and 9 are flat surfaces.

(Work Operation)

In a case where burring or grinding/polishing work on a surface is to be performed on a work using the polishing brush 1, the shank 5 is coupled to the head of a machine tool and rotated around the axis of center of rotation L, and the free ends (lower ends) of the grinding element bundles 22 are pressed against the surface of the work. When the wire-shaped grinding elements 21 included in the grinding element bundle 22 are worn due to the work operation and the length of the protrusion from the lower edge 6 a of the brush case 6 is reduced, the screws 8 and 9 secured to the grinding element holder 23 through the guide holes 14 and 15 are loosened. Then, the polishing brush body 7 is moved in the direction of the axis of center of rotation L in the inside of the brush case 6, and thereafter the screws 8 and 9 are tightened. With this operation, the position in the direction of the axis of center of rotation L of the polishing brush body 7 in the inside of the brush case 6 is adjusted, so that the length of the protrusion of the free end of the wire-shaped grinding element 21 from the brush case 6 is adjusted.

(Operation and Effects)

According to the first embodiment, the grinding element bundles 22 are inserted in the grinding element holding groove 28 provided to the grinding element holder 23 and fixed with the adhesive 29 filling the grinding element holding groove 28, rather than being inserted in holding holes adapted to the cross-sectional shape of each bundle 22. Therefore, even when the diameter size or the like of each grinding element bundle 22 is larger than the width of the grinding element holding groove 28, the grinding element bundle 22 is deformed to conform to the grinding element holding groove 28, whereby the base end portion 22 a of the grinding element bundle 22 can be inserted into the grinding element holding groove 28. Thus, even when each grinding element bundle 22 of the wire-shaped grinding elements 21 has a different diameter size, the grinding element bundles 22 can be held in the grinding element holder 23.

Furthermore, in the first embodiment, the grinding element bundles 22 held in the grinding element holder 23 are kept apart from each other to allow chips to be ejected efficiently during grinding work. In addition, since the grinding element bundles 22 held in the grinding element holder 23 are kept apart from each other, the heat dissipation effect is high. Moreover, when compared with a case in which the wire-shaped grinding elements 21 are held without a gap in the grinding element holding groove 28, the polishing brush 1 can be formed with a smaller amount of grinding elements.

In the first embodiment, each wire-shaped grinding element 21 is formed of an assembly of inorganic filaments impregnated and solidified with resin and has high hardness, thereby providing the polishing brush 1 with a high grinding/polishing capability even when the grinding element bundles 22 are held apart from each other in the grinding element holder 23.

Second Embodiment

FIG. 4(a) is an illustration of a polishing brush in a second embodiment to which the present invention is applied, and FIG. 4(b) is a perspective view of the grinding element holder for the polishing brush in the second embodiment. It is noted that the polishing brush 51 in the second embodiment has a configuration corresponding to the polishing brush 1 in the first embodiment, and the corresponding parts are denoted with the same reference signs and will not be further elaborated.

As shown in FIG. 4(a), the polishing brush 51 includes a shank member 52 having a shank 5 coupled to the head of a machine tool (drive device), an annular grinding element holder 23 through which the lower side portion of the shank member 52 passes, and a locknut 53 screwed onto the lower end portion of the shank member 52. The outer peripheral side surface of the grinding element holder 23 serves as a grinding member holding surface 27, and a plurality of grinding element bundles 22 protrude radially outward from the grinding member holding surface 27. The grinding element holder 23 and the grinding element bundles 22 constitute the polishing brush body 7.

The shank member 52 has the shank 5, a collar 54, and a bolt 55 from the top to the bottom. The outer peripheral surface of the bolt 55 has a male thread screwed into the locknut 53. A portion of the shank member 52 that is lower than the collar 54 is inserted in the center hole 24 of the grinding element holder 23 (see FIG. 4(b)), and the lower end portion of the bolt 55 protrudes downward from the grinding element holder 23.

The grinding element holder 23 has an annular grinding element holding groove (groove) 28 formed on its grinding member holding surface 27 around the axis of center of rotation L. The grinding element bundles 22 have respective base end portions 22 a inserted in the grinding element holding groove 28 in such a state as to be kept apart from each other and are fixed to the grinding element holder 23 with an adhesive 29 filling the grinding element holding groove 28. In the second embodiment, the grinding element bundles 22 are inserted and fixed at regular intervals in the grinding element holding groove 28. Each grinding element bundle 22 is made from the wire-shaped grinding elements 21 formed of an assembly of inorganic filaments impregnated and solidified with resin. Each grinding element bundle 22 is a bundle shaped in a circle.

The locknut 53 is screwed from below onto the lower end portion of the bolt 55 protruding downward from the grinding element holder 23. The locknut 53 is screwed onto the bolt 55 until the grinding element holder 23 becomes sandwiched between the collar 54 and the locknut 53 of the shank member 52, whereby the grinding element holder 23 is fixed to the shank member 52.

When burring or grinding/polishing work on a surface is performed on a work using the polishing brush 51, the shank 5 is coupled to the head of a machine tool and rotated around the axis of center of rotation L, and the free ends (the ends on the outer peripheral side) of the grinding element bundles 22 are pressed against the surface of the work. When the wire-shaped grinding elements 21 included in the grinding element bundle 22 are worn due to the work operation, the locknut 53 is loosened and removed from the shank member 52, and the grinding element holder 23 is then removed from the shank member 52 for replacement of the polishing brush body 7 alone with a new one.

The second embodiment can achieve the same operation and effects as in the first embodiment.

Other Embodiments

In each embodiment, a plurality of grinding element holding grooves 28 may be provided in the grinding element holder 23. The grinding element holding groove 28 may be provided linearly on the grinding member holding surface 27.

Although the wire-shaped grinding elements 21 are bundled into a circular shape in the foregoing examples, the wire-shaped grinding elements 21 may be bundled into other shapes. For example, the wire-shaped grinding elements 21 may be bundled such that the cross-sectional shape of the base end portion 22 a inserted as a grinding element bundle 22 in the grinding element holding groove 28 is oval, rectangular, or square.

In the foregoing examples, the wire-shaped grinding elements 21 are subdivided to form the grinding element bundles 22, and the grinding element bundles 22 are fixed to the grinding element holder 23 so as to be kept apart from each other. Alternatively, the wire-shaped grinding elements 21 may not be subdivided but may be arranged in an annular shape such that a first end portion of each wire-shaped grinding element 21 is inserted in the grinding element holding groove 28 to be fixed to the grinding element holder 23. Also in this case, it is possible to hold the wire-shaped grinding elements 21 in the grinding element holder 23 without strictly controlling the shape (the shape of arrangement of the wire-shaped grinding elements 21) of the wire-shaped grinding elements 21 to be held in the grinding element holder 23.

The wire-shaped grinding element 21 used may be formed of an assembly of silicon carbide fibers, carbon fibers, silicon nitride fibers, glass fibers, and the like impregnated and solidified with resin. Alternatively, the wire-shaped grinding element 21 used may be formed of nylon, abrasive-containing nylon, abrasive-containing rubber, stainless steel, brass, and the like. The grinding element bundle 22 may have a quadrangular shape in cross section. 

1. A polishing brush comprising: a plurality of wire-shaped grinding elements; and a grinding element holder holding the wire-shaped grinding elements, wherein the grinding element holder has a groove, and first end portions of the wire-shaped grinding elements are inserted in the groove and fixed to the grinding element holder with an adhesive filling the groove.
 2. The polishing brush according to claim 1, wherein the wire-shaped grinding elements are subdivided to form a plurality of grinding element bundles, and the grinding element bundles are fixed to the grinding element holder in such a state as to be kept apart from each other.
 3. The polishing brush according to claim 2, wherein the groove is an annular groove formed around the axis of center of rotation, and the grinding element bundles are inserted at regular intervals in the annular groove.
 4. The polishing brush according to claim 2, wherein each of the grinding element bundles has a circular shape in cross section in a direction orthogonal to a length direction of each of the wire-shaped grinding elements at an end portion of the grinding element bundle inserted in the groove.
 5. The polishing brush according to claim 1, wherein each of the wire-shaped grinding elements is formed of an assembly of inorganic filaments impregnated and solidified with resin. 